Diagnostics (Apr 2023)

Clinical Validation of a Colorimetric Loop-Mediated Isothermal Amplification Using a Portable Device for the Rapid Detection of SARS-CoV-2

  • Bruna W. Raddatz,
  • Felipe J. Rabello,
  • Rafael Benedetti,
  • Gisleine J. Steil,
  • Louise M. Imamura,
  • Edson Y. S. Kim,
  • Erika B. Santiago,
  • Luís F. Hartmann,
  • João V. Predebon,
  • Bruna M. Delfino,
  • Meri B. Nogueira,
  • Jucélia S. dos Santos,
  • Breno G. da Silva,
  • Diego R. P. Nicollete,
  • Bernardo M. M. de Almeida,
  • Sergio R. Rogal,
  • Marcus V. M. Figueredo

DOI
https://doi.org/10.3390/diagnostics13071355
Journal volume & issue
Vol. 13, no. 7
p. 1355

Abstract

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Quick and reliable mass testing of infected people is an effective tool for the contingency of SARS-CoV-2. During the COVID-19 pandemic, Point-of-Care (POC) tests using Loop-Mediated Isothermal Amplification (LAMP) arose as a useful diagnostic tool. LAMP tests are a robust and fast alternative to Polymerase Chain Reaction (PCR), and their isothermal property allows easy incorporation into POC platforms. The main drawback of using colorimetric LAMP is the reported short-term stability of the pre-mixed reagents, as well as the relatively high rate of false-positive results. Also, low-magnitude amplification can produce a subtle color change, making it difficult to discern a positive reaction. This paper presents Hilab Molecular, a portable device that uses the Internet of Things and Artificial Intelligence to pre-analyze colorimetric data. In addition, we established manufacturing procedures to increase the stability of colorimetric RT-LAMP tests. We show that ready-to-use reactions can be stored for up to 120 days at −20 °C. Furthermore, we validated both the Hilab Molecular device and the Hilab RT-LAMP test for SARS-CoV-2 using 581 patient samples without any purification steps. We achieved a sensitivity of 92.93% and specificity of 99.42% (samples with CT ≤ 30) when compared to RT-qPCR.

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